- Nedaplatin Combined With Gemcitabine in the Treatment of Recurrent and Metastatic Nasopharyngeal Carcinomaa Single Arm and Phase Clinical Trail: Condition: Recurrent and Metastatic Nasopharyngeal Carcinoma
Intervention: Drug: nedaplatin and gemcitabine
Sponsor: Sun Yat-sen UniversityThe purpose of this single arm,phase Ⅱ clinical trail is to determine the safety and efficacy of nedaplatin combined with gemcitabine in the treatment of recurrent and metastatic nasopharyngeal carcinomaCondition Intervention Phase Recurrent and Metastatic Nasopharyngeal Carcinoma Drug: nedaplatin and gemcitabine Phase 2 - Endoscopic repair of laryngeal cleft
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Author(s): Ozgul Gergin, Reza Rahbar, Eelam Adil
Laryngeal cleft (LC) is a rare congenital malformation of the posterior larynx. Diagnosis requires a high index of suspicion because type 1 clefts, which are the most common, can be easily overlooked by the endoscopist. Timely diagnosis and appropriate treatment of LC are essential to prevent permanent pulmonary injury. Presenting symptoms include aspiration, cough, recurrent pneumonia, and dysphagia, with a wide range of severity. A trial of feeding therapy remains the management of choice for type 1 LC. When conservative measures fail, the next step in management is surgical repair. Endoscopic repair of LC is a well-tolerated and a reliable approach that considerably reduces perioperative and postoperative morbidity in type 1, type 2, and select type 3 LCs. In this article, we describe the endoscopic management of LCs, highlighting surgical pearls necessary for success. - The Treatment of Chronic Aspiration
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Author(s): Ramon A. Franco, Inna Husain
Chronic aspiration can be a life-threatening disorder of variable etiology. Often patients, both pediatric and adult, have suffered neurological devastation placing them at an increased risk of morbidity and mortality from laryngeal incompetence and the inability to protect their airways from soilage. Numerous surgical procedures have been described to tackle this problem, however most definitive procedures cause damage to the intrinsic integrity of the larynx and are irreversible. Laryngotracheal separation with and without diversion is a definitive treatment option for intractable aspiration that is technically simple while still preserving the larynx for the possibility of future reversal. It is effective with a low complication profile. This paper will address the indications, advantages, and surgical technique to laryngotracheal separation with or without diversion. - Cricopharyngeal dysfunction and Zenker’s Diverticulum
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Author(s): Colin Huntley, Joseph Spiegel, Maurits Boon
Cricopharyngeal dysfunction and Zenker’s Diverticulum are seen more commonly as our population ages and both the entities lead to clinical and quality-of-life derangements. Many practitioners prefer an endoscopic approach for the treatment of these problems, yet surgeons still need to be familiar with open techniques. The open approaches are still necessary for those patients who have failed an endoscopic approach or are not a candidate for the procedure because of anatomical limitations. As such, the surgeon must be comfortable with both the methods to provide effective care for patients with these issues. - Non-Zenker Hypopharyngeal Diverticula
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Author(s): Christopher M. Johnson, Gregory N. Postma
Zenker diverticulum is the most common hypopharyngeal diverticulum. Alternate types of hypopharyngeal diverticula are uncommon; however, recognition and proper diagnosis is imperative, as treatment may be quite different. Hypopharyngeal diverticula are typically diagnosed using barium esophagography and differences between types of diverticula can be subtle. Although endoscopic management of Zenker Diverticula has become very popular recently, endoscopic exposure of other hypopharyngeal diverticula is not as straightforward. In this article, traction, iatrogenic, Killian-Jamieson, and Laimer diverticula would be discussed. Treatment options for each would also be explored and compared with treatment of the more common Zenker diverticulum. - Therapeutic ADC Targeting SLITRK6 in Bladder CancerSLITRK6 is a member of the SLITRK family of neuronal transmembrane proteins that was discovered as a bladder tumor antigen using suppressive subtractive hybridization. Extensive immunohistochemistry showed SLITRK6 to be expressed in multiple epithelial tumors, including bladder, lung, and breast cancer as well as in glioblastoma. To explore the possibility of using SLITRK6 as a target for an antibody–drug conjugate (ADC), we generated a panel of fully human mAbs specific for SLITRK6. ADCs showed potent in vitro and in vivo cytotoxic activity after conjugation to Monomethyl Auristatin E or Monomethyl Auristatin F. The most potent ADC, ASG-15ME, was selected as the development candidate and given the product name AGS15E. ASG-15ME is currently in phase I clinical trials for the treatment of metastatic urothelial cancer. This is the first report that SLITRK6 is a novel antigen in bladder cancer and also the first report of the development of ASG-15ME for the treatment of metastatic bladder cancer. Mol Cancer Ther; 15(6); 1301–10. ©2016 AACR.
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via IFTTT - Unbiased Oncology Combination ScreenCombination drug therapy is a widely used paradigm for managing numerous human malignancies. In cancer treatment, additive and/or synergistic drug combinations can convert weakly efficacious monotherapies into regimens that produce robust antitumor activity. This can be explained in part through pathway interdependencies that are critical for cancer cell proliferation and survival. However, identification of the various interdependencies is difficult due to the complex molecular circuitry that underlies tumor development and progression. Here, we present a high-throughput platform that allows for an unbiased identification of synergistic and efficacious drug combinations. In a screen of 22,737 experiments of 583 doublet combinations in 39 diverse cancer cell lines using a 4 by 4 dosing regimen, both well-known and novel synergistic and efficacious combinations were identified. Here, we present an example of one such novel combination, a Wee1 inhibitor (AZD1775) and an mTOR inhibitor (ridaforolimus), and demonstrate that the combination potently and synergistically inhibits cancer cell growth in vitro and in vivo. This approach has identified novel combinations that would be difficult to reliably predict based purely on our current understanding of cancer cell biology. Mol Cancer Ther; 15(6); 1155–62. ©2016 AACR.
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via IFTTT - DETD-35 Overcomes Acquired Vemurafenib Resistance in MiceAcquired resistance to vemurafenib develops through reactivation of RAF/MEK/ERK signaling or bypass mechanisms. Recent combination therapies such as a MEK inhibitor combined with vemurafenib show improvement in major clinical end points, but the percentage of patients with adverse toxic events is higher than with vemurafenib monotherapy and most patients ultimately relapse. Therefore, there is an urgent need to develop new antimelanoma drugs and/or adjuvant agents for vemurafenib therapy. In this study, we created a novel semiorganically modified derivative, DETD-35, from deoxyelephantopin (DET), a plant sesquiterpene lactone demonstrated as an anti-inflammatory and anti–mammary tumor agent. Our results show that DETD-35 inhibited proliferation of a panel of melanoma cell lines, including acquired vemurafenib resistance A375 cells (A375-R) established in this study, with superior activities to DET and no cytotoxicity to normal melanocytes. DETD-35 suppressed tumor growth and reduced tumor mass as effectively as vemurafenib in A375 xenograft study. Furthermore, DETD-35 also reduced tumor growth in both acquired (A375-R) and intrinsic (A2058) vemurafenib resistance xenograft models, where vemurafenib showed no antitumor activity. Notably, the combination of DETD-35 and vemurafenib exhibited the most significant effects in both in vitro and in vivo xenograft studies due to synergism of the compound and the drug. Mechanistic studies suggested that DETD-35 overcame acquired vemurafenib resistance at least in part through deregulating MEK-ERK, Akt, and STAT3 signaling pathways and promoting apoptosis of cancer cells. Overall, our results suggest that DETD-35 may be useful as a therapeutic or adjuvant agent against BRAFV600E mutant and acquired vemurafenib resistance melanoma. Mol Cancer Ther; 15(6); 1163–76. ©2016 AACR.
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via IFTTT - Targeting ANT2 in EGFR-TKI-Resistant NSCLCEGFR tyrosine kinase inhibitor (EGFR-TKI) therapy has achieved favorable clinical outcomes in non–small cell lung cancer (NSCLC) patients with EGFR mutations. However, patients eventually develop resistance to EGFR-TKIs by several mechanisms. Adenine nucleotide translocase-2 (ANT2) is an oncogenic mitochondrial membrane–associated protein. We investigated the therapeutic potential of ANT2 inhibition to EGFR-TKI resistance in NSCLC using gefitinib-sensitive (PC9 and HCC827) and gefitinib-resistant (H1975 and HCC827/GR) NSCLC cell lines. ANT2 was inhibited by transfecting cells with an ANT2-specific shRNA. ANT2 expression was elevated in the H1975 and HCC827/GR cells compared with the PC9 and HCC827 cells. ANT2 upregulation in gefitinib-resistant cells was associated with increased SP1 binding to the ANT2 promoter. ANT2-specific shRNA decreased NSCLC cell viability. Moreover, ANT2-specific shRNA sensitized the H1975 and HCC827/GR cells to gefitinib, accompanied by HSP90 and EGFR downregulation. ANT2-specific shRNA also inactivated the PI3K/Akt signaling pathway in the H1975 and HCC827/GR cells, which was mediated by the suppression of miR-221/222 levels and by the subsequent restoration of PTEN. In EGFR-TKI–treated NSCLC patients, ANT2 expression was higher in patients exhibiting poor responses compared with patients showing excellent responses. Furthermore, ANT2 expression increased in tumor tissues biopsied after acquiring gefitinib resistance compared with tissues before gefitinib treatment. These findings suggest that ANT2 overexpression contributes to EGFR-TKI resistance in NSCLC and that ANT2 targeting may be considered a novel strategy for overcoming this resistance. Mol Cancer Ther; 15(6); 1387–96. ©2016 AACR.
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via IFTTT - Dll4 Inhibition in Ovarian CancerDelta-like ligand 4 (Dll4), one of the Notch ligands, is overexpressed in ovarian cancer, especially in tumors resistant to anti-VEGF therapy. Here, we examined the biologic effects of dual anti-Dll4 and anti-VEGF therapy in ovarian cancer models. Using Dll4-Fc blockade and anti-Dll4 antibodies (murine REGN1035 and human REGN421), we evaluated the biologic effects of Dll4 inhibition combined with aflibercept or chemotherapy in orthotopic mouse models of ovarian cancer. We also examined potential mechanisms by which dual Dll4 and VEGF targeting inhibit tumor growth using immunohistochemical staining for apoptosis and proliferation markers. Reverse-phase protein arrays were used to identify potential downstream targets of Dll4 blockade. Dual targeting of VEGF and Dll4 with murine REGN1035 showed superior antitumor effects in ovarian cancer models compared with either monotherapy. In the A2780 model, REGN1035 (targets murine Dll4) or REGN421 (targets human Dll4) reduced tumor weights by 62% and 82%, respectively; aflibercept alone reduced tumor weights by 90%. Greater therapeutic effects were observed for Dll4 blockade (REGN1035) combined with either aflibercept or docetaxel (P< 0.05 for the combination vs. aflibercept). The superior antitumor effects of REGN1035 and aflibercept were related to increased apoptosis in tumor cells compared with the monotherapy. We also found that GATA3 expression was significantly increased in tumor stroma from the mice treated with REGN1035 combined with docetaxel or aflibercept, suggesting an indirect effect of these combination treatments on the tumor stroma. These findings identify that dual targeting of Dll4 and VEGF is an attractive therapeutic approach. Mol Cancer Ther; 15(6); 1344–52. ©2016 AACR.
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via IFTTT - Targeting Hh Pathway by MK-4101 in Medulloblastoma and BCCAberrant activation of the Hedgehog (Hh) signaling pathway is implicated in the pathogenesis of many cancers, including medulloblastoma and basal cell carcinoma (BCC). In this study, using neonatally irradiated Ptch1+/–mice as a model of Hh-dependent tumors, we investigated the in vivo effects of MK-4101, a novel SMO antagonist, for the treatment of medulloblastoma and BCC. Results clearly demonstrated a robust antitumor activity of MK-4101, achieved through the inhibition of proliferation and induction of extensive apoptosis in tumor cells. Of note, beside antitumor activity on transplanted tumors, MK-4101 was highly efficacious against primary medulloblastoma and BCC developing in the cerebellum and skin of Ptch1+/– mice. By identifying the changes induced by MK-4101 in gene expression profiles in tumors, we also elucidated the mechanism of action of this novel, orally administrable compound. MK-4101 targets the Hh pathway in tumor cells, showing the maximum inhibitory effect on Gli1. MK-4101 also induced deregulation of cell cycle and block of DNA replication in tumors. Members of the IGF and Wnt signaling pathways were among the most highly deregulated genes by MK-4101, suggesting that the interplay among Hh, IGF, and Wnt is crucial in Hh-dependent tumorigenesis. Altogether, the results of this preclinical study support a therapeutic opportunity for MK-4101 in the treatment of Hh-driven cancers, also providing useful information for combination therapy with drugs targeting pathways cooperating with Hh oncogenic activity. Mol Cancer Ther; 15(6); 1177–89. ©2016 AACR.
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- CS-IVa-Be, a Novel IL6R Antagonist, Inhibits IL6/STAT3The activation of IL6/STAT3 signaling is associated with the pathogenesis of many cancers. Agents that suppress IL6/STAT3 signaling have cancer-therapeutic potential. In this study, we found that chikusetsusaponin IVa butyl ester (CS-IVa-Be), a triterpenoid saponin extracted from Acanthopanas gracilistylus W.W.Smith, induced cancer cell apoptosis. CS-IVa-Be inhibited constitutive and IL6-induced STAT3 activation, repressed STAT3 DNA-binding activity, STAT3 nuclear translocation, IL6-induced STAT3 luciferase reporter activity, IL6-induced STAT3-regulated antiapoptosis gene expression in MDA-MB-231 cells, and IL6-induced TF-1 cell proliferation. Surprisingly, CS-IVa-Be inhibited IL6 family cytokines rather than other cytokines induced STAT3 activation. Further studies indicated that CS-IVa-Be is an antagonist of IL6 receptor via directly binding to the IL6Rα with aKd of 663 ± 74 nmol/L and the GP130 (IL6Rβ) with a Kd of 1,660 ± 243 nmol/L, interfering with the binding of IL6 to IL6R (IL6Rα and GP130) in vitro and in cancer cells. The inhibitory effect of CS-IVa-Be on the IL6–IL6Rα–GP130 interaction was relatively specific as CS-IVa-Be showed higher affinity to IL6Rα than to LIFR (Kd: 4,910 ± 1,240 nmol/L) and LeptinR (Kd: 4,990 ± 915 nmol/L). We next demonstrated that CS-IVa-Be not only directly induced cancer cell apoptosis but also sensitized MDA-MB-231 cells to TRAIL-induced apoptosis via upregulating DR5. Our findings suggest that CS-IVa-Be as a novel IL6R antagonist inhibits IL6/STAT3 signaling pathway and sensitizes the MDA-MB-231 cells to TRAIL-induced cell death. Mol Cancer Ther; 15(6); 1190–200. ©2016 AACR.
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via IFTTT - Trastuzumab Dysregulates HER2 and Inhibits AutophagyDysregulation of autophagy has been implicated in various cardiovascular diseases. Trastuzumab, a humanized monoclonal antibody, binds to HER2 domain IV and is approved for the treatment of HER2-positive breast cancer. Trastuzumab therapy is associated with considerable cardiotoxicity, the mechanism of which remains unclear. HER2 signaling plays a pivotal role in cardiomyocyte development and survival and is essential for the prevention of cardiomyopathy. However, a direct link has not been confirmed between trastuzumab-induced cardiomyopathy and impaired HER2 signaling. Our data reveal a novel mechanism by which trastuzumab dysregulates HER2 signaling and impairs basal autophagic process in human primary cardiomyocytes. Specifically, trastuzumab treatment leads to the phosphorylation of HER1-Y845 and HER2-Y1248 and the activation of Erk. This in turn results in upregulation of mTOR signaling pathway and subsequently inhibition of autophagy in primary cardiomyocytes and C57BL/6 mice. Trastuzumab-induced downregulation of autophagy is further supported by the fact that trastuzumab treatment reduces protein levels of autophagosome-associated signaling molecules such as Atg 5-12, Atg 7, Atg 14, and Beclin 1. We further demonstrated that trastuzumab-mediated inhibition of autophagy resulted in the increased production of reactive oxygen species (ROS) in cardiomyocytes. Pertuzumab, another anti-HER2 therapeutic mAb binding to HER2 domain II, fails to modulate HER2 signaling and is unable to inhibit autophagy and to increase ROS production in cardiomyocytes. This study provides novel mechanistic insights into trastuzumab-induced cardiotoxicity, which may assist in formulating novel approaches for clinical management of trastuzumab-induced cardiomyopathy. Mol Cancer Ther; 15(6); 1321–31. ©2016 AACR.
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via IFTTT - Stem Cell-Based Gene Therapy for Bladder CancerBladder cancer is a significant clinical and economic problem. Despite intravesical chemotherapy and immunotherapy, up to 80% of patients with non–muscle-invasive bladder cancer develop recurrent tumors, of which 20% to 30% evolve into more aggressive, potentially lethal tumors. Recently, bladder cancer cells are considered to be mediators of resistance to current therapies and therefore represent strong candidates as biologic targets. No effective chemotherapy has yet been developed for advanced bladder cancer. It is desirable that a drug can be delivered directly and specifically to bladder cancer cells. Stem cells have selective migration ability toward cancer cells, and therapeutic genes can be easily transduced into stem cells. In suicide gene therapy for cancer, stem cells carry a gene encoding a carboxylesterase (CE) enzyme that transforms an inert CPT-11 prodrug into a toxic SN-38 product, a topoisomerase 1 inhibitor. In immunodeficient mice, systemically transplanted HB1.F3.CE stem cells migrated toward the tumor implanted by the TCCSUP bladder cancer cell line, and, in combination with CPT-11, the volume of tumors was significantly reduced. These findings may contribute to the development of a new selective chemotherapeutic strategy against bladder cancer. Mol Cancer Ther; 15(6); 1201–7. ©2016 AACR.
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via IFTTT - miR-29b/HDAC4 Epigenetic Loop in Multiple MyelomaEpigenetic abnormalities are common in hematologic malignancies, including multiple myeloma, and their effects can be efficiently counteracted by a class of tumor suppressor miRNAs, named epi-miRNAs. Given the oncogenic role of histone deacetylases (HDAC) in multiple myeloma, we investigated whether their activity could be antagonized by miR-29b, a well-established epi-miRNA. We demonstrated here that miR-29b specifically targets HDAC4 and highlighted that both molecules are involved in a functional loop. In fact, silencing of HDAC4 by shRNAs inhibited multiple myeloma cell survival and migration and triggered apoptosis and autophagy, along with the induction of miR-29b expression by promoter hyperacetylation, leading to the downregulation of prosurvival miR-29b targets (SP1, MCL-1). Moreover, treatment with the pan-HDAC inhibitor SAHA upregulated miR-29b, overcoming the negative control exerted by HDAC4. Importantly, overexpression or inhibition of miR-29b, respectively, potentiated or antagonized SAHA activity on multiple myeloma cells, as also shown in vivo by a strong synergism between miR-29b synthetic mimics and SAHA in a murine xenograft model of human multiple myeloma. Altogether, our results shed light on a novel epigenetic circuitry regulating multiple myeloma cell growth and survival and open new avenues for miR-29b–based epi-therapeutic approaches in the treatment of this malignancy. Mol Cancer Ther; 15(6); 1364–75. ©2016 AACR.
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via IFTTT - Apratoxin A, a Novel Pancreas-Targeting AgentApratoxin A is a natural product with potent antiproliferative activity against many human cancer cell lines. However, we and other investigators observed that it has a narrow therapeutic window in vivo. Previous mechanistic studies have suggested its involvement in the secretory pathway as well as the process of chaperone-mediated autophagy. Still the link between the biologic activities of apratoxin A and its in vivo toxicity has remained largely unknown. A better understanding of this relationship is critically important for any further development of apratoxin A as an anticancer drug. Here, we describe a detailed pathologic analysis that revealed a specific pancreas-targeting activity of apratoxin A, such that severe pancreatic atrophy was observed in apratoxin A–treated animals. Follow-up tissue distribution studies further uncovered a unique drug distribution profile for apratoxin A, showing high drug exposure in pancreas and salivary gland. It has been shown previously that apratoxin A inhibits the protein secretory pathway by preventing cotranslational translocation. However, the molecule targeted by apratoxin A in this pathway has not been well defined. By using a 3H-labeled apratoxin A probe and specific Sec 61α/β antibodies, we identified that the Sec 61 complex is the molecular target of apratoxin A. We conclude that apratoxin A in vivo toxicity is likely caused by pancreas atrophy due to high apratoxin A exposure. Mol Cancer Ther; 15(6); 1208–16. ©2016 AACR.
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via IFTTT - TWIST1 Polymorphism Predicts Bevacizumab EfficacyThe epithelial–mesenchymal transition (EMT) is an important mechanism of resistance to angiogenesis inhibition. The ability of EMT pathway genetic variants to predict the efficacy of antiangiogenic therapy is unknown. We analyzed associations between functional SNPs in EMT-related genes and outcomes in metastatic colorectal cancer (mCRC) patients undergoing first-line bevacizumab-based chemotherapy. A total of 220 mCRC patients were included in this study: 143 patients treated with first-line bevacizumab-based chemotherapy (bevacizumab cohort) and 77 patients treated with cetuximab-based chemotherapy (cetuximab cohort). SNPs in TWIST1(rs2285682, rs2285681), ZEB1 (rs10826943, rs2839658), SNAIL (rs1543442, rs4647958), and E-cadherin(rs16260) genes were analyzed by PCR-based direct sequencing. Patients carrying a TWIST1 rs2285682 G allele had a significantly longer median progression-free survival (PFS) of 18.1 months and overall survival (OS) of 44.1 months compared with those with the T/T genotype, who had a median PFS of 13.3 months (HR, 0.57; P = 0.003) and OS of 29.2 months (HR, 0.53; P = 0.001) in the bevacizumab cohort. In multivariate analysis, associations between TWIST1 rs2285682 and PFS and OS remained significant. Among women, the G allele ofTWIST1 rs2285682 (PFS HR, 0.39; P = 0.007; OS HR, 0.30; P = 0.001) and TWIST1 rs2285681 (PFS HR, 0.27; P< 0.001; OS HR, 0.25; P < 0.001) was associated with improved survival. No significant associations were found in the cetuximab cohort. Our findings suggest that TWIST1 polymorphisms are associated with survival in mCRC patients treated with first-line bevacizumab-based chemotherapy and may serve as clinically useful biomarkers for antiangiogenic therapy. Mol Cancer Ther; 15(6); 1405–11. ©2016 AACR.
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via IFTTT - Knottin-Fc-Drug Con{#x0237}ugate as an Antitumor AgentAntibody–drug conjugates (ADC) have generated significant interest as targeted therapeutics for cancer treatment, demonstrating improved clinical efficacy and safety compared with systemic chemotherapy. To extend this concept to other tumor-targeting proteins, we conjugated the tubulin inhibitor monomethyl-auristatin-F (MMAF) to 2.5F–Fc, a fusion protein composed of a human Fc domain and a cystine knot (knottin) miniprotein engineered to bind with high affinity to tumor-associated integrin receptors. The broad expression of integrins (including αvβ3, αvβ5, and α5β1) on tumor cells and their vasculature makes 2.5F-Fc an attractive tumor-targeting protein for drug delivery. We show that 2.5F-Fc can be expressed by cell-free protein synthesis, during which a non-natural amino acid was introduced into the Fc domain and subsequently used for site-specific conjugation of MMAF through a noncleavable linker. The resulting knottin–Fc–drug conjugate (KFDC), termed 2.5F-Fc-MMAF, had approximately 2 drugs attached per KFDC. 2.5F–Fc–MMAF inhibited proliferation in human glioblastoma (U87MG), ovarian (A2780), and breast (MB-468) cancer cells to a greater extent than 2.5F–Fc or MMAF alone or added in combination. As a single agent, 2.5F–Fc–MMAF was effective at inducing regression and prolonged survival in U87MG tumor xenograft models when administered at 10 mg/kg two times per week. In comparison, tumors treated with 2.5F–Fc or MMAF were nonresponsive, and treatment with a nontargeted control, CTRL–Fc–MMAF, showed a modest but not significant therapeutic effect. These studies provide proof-of-concept for further development of KFDCs as alternatives to ADCs for tumor targeting and drug delivery applications. Mol Cancer Ther; 15(6); 1291–300. ©2016 AACR.
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via IFTTT - Targeting the BET Family in Colorectal CancerInhibitors of the bromodomain and extraterminal domain (BET) protein family attenuate the proliferation of several tumor cell lines. These effects are mediated, at least in part, through repression of c-MYC. In colorectal cancer, overexpression of c-MYC due to hyperactive WNT/β-catenin/TCF signaling is a key driver of tumor progression; however, effective strategies to target this oncogene remain elusive. Here, we investigated the effect of BET inhibitors (BETi) on colorectal cancer cell proliferation and c-MYC expression. Treatment of 20 colorectal cancer cell lines with the BETi JQ1 identified a subset of highly sensitive lines. JQ1 sensitivity was higher in cell lines with microsatellite instability but was not associated with the CpG island methylator phenotype, c-MYC expression or amplification status, BET protein expression, or mutation status of TP53, KRAS/BRAF, orPIK3CA/PTEN. Conversely, JQ1 sensitivity correlated significantly with the magnitude of c-MYC mRNA and protein repression. JQ1-mediated c-MYC repression was not due to generalized attenuation of β-catenin/TCF-mediated transcription, as JQ1 had minimal effects on other β-catenin/TCF target genes or β-catenin/TCF reporter activity. BETi preferentially target super-enhancer–regulated genes, and a super-enhancer in c-MYC was recently identified in HCT116 cells to which BRD4 and effector transcription factors of the WNT/β–catenin/TCF and MEK/ERK pathways are recruited. Combined targeting of c-MYC with JQ1 and inhibitors of these pathways additively repressed c-MYC and proliferation of HCT116 cells. These findings demonstrate that BETi downregulate c-MYC expression and inhibit colorectal cancer cell proliferation and identify strategies for enhancing the effects of BETi on c-MYC repression by combinatorial targeting the c-MYC super-enhancer. Mol Cancer Ther; 15(6); 1217–26. ©2016 AACR.
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Πέμπτη 2 Ιουνίου 2016
OtoRhinoLaryngology & Medicine,New Articles,June 3rd,2016
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